Reply Obj. 2: This clarity is said to have been imaginary, not as though it were not really the clarity of glory, but because it was a kind of image representing that perfection of glory, in virtue of which the body will be glorious.
Reply Obj. 3: Just as the clarity which was in Christ's body was a representation of His body's future clarity, so the clarity which was in His garments signified the future clarity of the saints, which will be surpassed by that of Christ, just as the brightness of the snow is surpassed by that of the sun. Hence Gregory says (Moral. xxxii) that Christ's garments became resplendent, "because in the height of heavenly clarity all the saints will cling to Him in the refulgence of righteousness. For His garments signify the righteous, because He will unite them to Himself," according to Isa. 49:18: "Thou shalt be clothed with all these as with an ornament."
The bright cloud signifies the glory of the Holy Ghost or the "power of the Father," as Origen says (Tract. iii in Matth.), by which in the glory to come the saints will be covered. Or, again, it may be said fittingly that it signifies the clarity of the world redeemed, which clarity will cover the saints as a tent. Hence when Peter proposed to make tents, "a bright cloud overshaded" the disciples. _______________________
THIRD ARTICLE [III, Q. 45, Art. 3]
Whether the Witnesses of the Transfiguration Were Fittingly Chosen?
Objection 1: It would seem that the witnesses of the transfiguration were unfittingly chosen. For everyone is a better witness of things that he knows. But at the time of Christ's transfiguration no one but the angels had as yet any knowledge from experience of the glory to come. Therefore the witnesses of the transfiguration should have been angels rather than men.
Obj. 2: Further, truth, not fiction, is becoming in a witness of the truth. Now, Moses and Elias were there, not really, but only in appearance; for a gloss on Luke 9:30, "They were Moses and Elias," says: "It must be observed that Moses and Elias were there neither in body nor in soul"; but that those bodies were formed "of some available matter. It is also credible that this was the result of the angelic ministries, through the angels impersonating them." Therefore it seems that they were unsuitable witnesses.
Obj. 3: Further, it is said (Acts 10:43) that "all the prophets give testimony" to Christ. Therefore not only Moses and Elias, but also all the prophets, should have been present as witnesses.
Obj. 4: Further, Christ's glory is promised as a reward to all the faithful (2 Cor. 3:18; Phil. 3:21), in whom He wished by His transfiguration to enkindle a desire of that glory. Therefore He should have taken not only Peter, James, and John, but all His disciples, to be witnesses of His transfiguration.
On the contrary is the authority of the Gospel.